Study of ferroelectric domain walls offers a new nanoscale conduction path

Feb 22, 2012
Study of Ferroelectric domain walls offers a new nanoscale conduction path
SPM images of the (110) surface of cleaved h-HoMnO3. (top) PFM image showing in-plane ferroelectric domains (oriented vertically, red arrows). (bottom) cAFM image showing enhanced conduction along tail-to-tail domain walls; images are 4 microns per side.

(PhysOrg.com) -- Facility users from Rutgers University together with the Center for Nanoscale Materials' Electronic & Magnetic Materials & Devices Group have identified two-dimensional sheets of charge formed at the boundaries of ferroelectric domains in a multiferroic material.

These two-dimensional charged sheets are not pinned by unstable defects, chemical dopants, or structural interface, but are formed naturally as the inevitable by-products of topological vortices. This discovery is an important step in understanding the semiconducting properties of the domains and in small-gap ferroelectrics.

It also suggests a new and natural platform for exploring transport of charge carriers confined at interfaces or surfaces, which is one of the major playgrounds in condensed matter physics for emergent phenomena.

The team focused on hexagonal HoMnO3, which is a multiferroic material where antiferromagnetism and ferroelectricity coexist and — most intriguingly — magnetic, electric, and mechanical forces can be coupled to one another. In order to measure these various material properties simultaneously and on nanometer length scales, the researchers used in situ conductive atomic force microscopy (cAFM), piezo-response force microscopy (PFM), and Kelvin-probe force microscopy (KPFM) at low temperatures.

The results demonstrate that topological defects can be harnessed to stabilize charged 180-deg domain walls in multiferroics, opening up opportunities for a new kind of nanoscale conduction channel in multifunctional devices. Charged ferroelectric domain walls may provide novel platforms for creating a correlated two-dimensional electron gas without chemical doping.

Explore further: Scanning tunnelling microscopy: Computer simulations sharpen insights into molecules

More information: W. Wu et al., “Conduction of topologically-protected charged ferroelectric domain walls,” Phys. Rev. Lett., 108, 077203 (2012).

add to favorites email to friend print save as pdf

Related Stories

Structural consequences of nanolithography

Aug 11, 2011

(PhysOrg.com) -- Users from the University of Wisconsin-Madison and the Center for Nanophase Materials Science, working with the X-Ray Microscopy Group, have discovered structural effects accompanying the ...

Domain walls that conduct electricity

Jan 29, 2009

The logic and memory functions of future electronic devices could shrink dramatically - to one or two nanometers (billionths of a meter) instead of the many tens of nanometers that characterize today's most ...

Small and stable ferroelectric domains

Mar 28, 2011

Researchers are one step closer to figuring out a way to make nano-sized ferroelectric domains more stable, reports a new study in journal Science.

Recommended for you

Protons fuel graphene prospects

Nov 26, 2014

Graphene, impermeable to all gases and liquids, can easily allow protons to pass through it, University of Manchester researchers have found.

Cooling with the coldest matter in the world

Nov 24, 2014

Physicists at the University of Basel have developed a new cooling technique for mechanical quantum systems. Using an ultracold atomic gas, the vibrations of a membrane were cooled down to less than 1 degree ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.